The Periodic Table Review Concepts

Demetri Mendeleev By 1860 about 60 elements were known and a method was needed for organization.  In 1869, Russian chemist Dimitri Mendeleev proposed arranging elements by atomic weights and properties. The table contained gaps but Mendeleev predicted the discovery of new elements.

Important Features Atomic Number Symbol Name Atomic Mass We’ll learn more about these later…

What is the ATOMIC NUMBER? The number of protons found in the nucleus of an atom Or The number of electrons surrounding the nucleus of an atom.

What is the SYMBOL? An abbreviation of the element name.

What is the ATOMIC WEIGHT? The number of protons and neutrons in the nucleus of an atom.

How do I find the number of protons, electrons, and neutrons in an element using the periodic table? # of PROTONS = ATOMIC NUMBER # of ELECTRONS = ATOMIC NUMBER # of NEUTRONS = ATOMIC _ ATOMIC WEIGHT NUMBER

Elements share traits by FAMILIES (GROUPS) and PERIODS

The Elements are Separated into 9 Different Families on the Periodic Table 1. Alkali Metals 2. Alkaline Earth Metals 3. Transition Metals 4. Rare Earth Metals 5. Halogens 6. Noble Gases 7. Metalloids 8. Non-Metals 9. Other Metals

FAMILIES : Alkali Metals Very reactive metals that do not occur freely in nature Often found in salts Malleable, ductile, good conductors of heat and electricity. Can explode if they are exposed to water

FAMILIES : Alkaline Earth Metals Very reactive Not found free in nature

FAMILIES : Transition Metals Ductile And malleable, and conduct electricity and heat Iron, cobalt, and nickel, are the only elements known to produce a magnetic field

FAMILIES : Rare Earth Metals Many are man-made

FAMILIES : Halogens "Halogen" means "salt-former" and compounds containing halogens are called "salts" Exist in all three states of matter Usually bond with alkali metals to form basic salts

FAMILIES: Noble Gases Unreactive Inert Elements

Metalloids have Properties of both metals and non-metals Some of the metalloids are semi- conductors. This means that they can carry an electrical charge under special conditions. This property makes metalloids useful in computers and calculators (“Silicon Valley”)

Non-Metals Not able to conduct electricity or heat very well Very brittle Do not reflect light

Other Metals Ductile and Malleable Many are man-made Solid with a relatively high density Opaque

Metals Non-Metals Metalloids To Summarize: They are solid (except Mercury) They are shiny, good conductors of electricity and heat. They are ductile and malleable Metals Brittle (not malleable or ductile) Poor conductors of both heat and electricity Non-Metals Contain properties of both metals and non-metals Metalloids

Other Trends: Reactivity